Flatstich and flatlock in long foams is recommended to warm water (16C /62F degrees). Stitch looks like a "railway tracks". Inside and outside stitch look the same. Weave of leading and joining thread from both sides goes same way. Internal stitch is flat and more comfortable in contact with the skin than the overlock stitches. In this case a small amount of the water can get into the suit too.

Hidden stitch for glueing / vulcanisation of rubber surfaces on the neoprene in long foams is recommended for the cooler water. This construction is the best for cooler water because the seams are covered with rubber. Seam looks like a flatstich, it is just narrower. Water penetration into this suit is very difficult but it can happen.

Hidden tape seam for glueing (vulcanisation) of the neoprene rubber surface for long foams is recommended for extremely low temperatures of 10 degrees Celsius (50F) or even lower. Stitch is similarly used to join the neoprene suit. Stitches are additionally reinforced and "covered". Water penetration into this suit is even more difficult but still it is normal.